Calculators & everyday math
How to Count the Days Between Two Dates
Counting the days between two dates by hand is easy to get slightly wrong, especially across month ends and year boundaries. This guide shows a reliable method, a shortcut with day-of-year numbers, a spreadsheet formula, and checks that catch the usual errors.
Ready to try the tool this guide describes?
By hand
- Count the days left in the starting month after the start date: March 20 to March 31 is 11 days.
- Add the full months in between: April has 30 days and May has 31.
- Add the day of the month of the end date: June 10 adds 10.
- Total: 11 + 30 + 31 + 10 = 82 days from March 20 to June 10.
With day-of-year numbers
Within one year, subtract the day-of-year numbers. In 2026, March 20 is day 79 and June 10 is day 161, so the gap is 161 − 79 = 82 days. In a leap year, every date after February 28 has a day number one higher.
In a spreadsheet
Subtract the earlier date cell from the later one, for example =B2-A2, and format the result as a number. Add 1 if both dates should be counted.
Quick checks
- Across a year boundary: December 31 to January 1 is 1 day.
- A full year, January 1 to January 1, is 365 days — or 366 when a February 29 falls in between.
- The same date is 0 days apart, or 1 day if that date itself is being counted.
Count Days Between Dates FAQ
- How do I work out the number of days between two dates?
- Count the days left in the first month, add the full months in between, and add the days into the last month — or subtract the dates in a spreadsheet.
- How many days are there from January 1 to December 31?
- 364 days apart in a year like 2026, or 365 if you count both dates.
- How do I count days in Excel or Google Sheets?
- Subtract the two date cells, such as =B2-A2.
- Are weekends included?
- Yes, in a calendar-day count. Counting only weekdays or business days is a different calculation.
- Does daylight saving time change the count?
- Not when you count calendar dates. It only matters when you subtract clock times across the change.
Related guides
- Inclusive vs. ExclusiveWhy the 1st to the 3rd can be 2 days or 3, when to count both the start and end date, and examples from hotel stays, events, and deadlines.
- Leap Years and Day CountsWhich years are leap years, how February 29 changes day counts, and why 365 days after a date isn’t always the same date a year later.
Open the tool
Jump into Days Between Dates Calculator when you are ready to process your files.
